1. Field of the Invention
This invention relates generally to tools for drilling machines.
2. Description of the Related Art
There are many different types of drilling machines for drilling through a formation. Some of these drilling machines are mobile and others are stationary. Examples of mobile and stationary drilling machines are disclosed in U.S. Pat. Nos. 3,245,180, 3,692,123, 3,708,024, 3,778,940, 3,815,690, 3,833,072, 3,905,168, 3,968,845, 3,992,831, 4,020,909, 4,595,065, 5,988,299, 6,672,410, 6,675,915, 7,325,634, 7,347,285 and 7,413,036. Some drilling machines, such as the one disclosed in U.S. Pat. No. 4,295,758, are designed to float and are useful for ocean drilling.
One type of drilling machine includes a tower and a rotary head movable along the tower, as well as a platform. The platform has a generally horizontal upper surface with an opening through which a drill string is moveable. The rotary head is movable along the tower and engageable with the drill string. A drill string includes one or more drill pipes connected together, and allows the borehole to be formed to a depth greater than the length of a single drill pipe. One of the drill pipes of the drill string is attached to an earth bit to facilitate its ability to drill through the formation. Hence, the drill string includes drill pipes which are capable of being attached to an earth bit. The borehole is formed in response to rotating the drill string and earth bit with the rotary head, and forcing them downwardly through the formation.
The drill pipes of the drill string can be connected together in many different ways. For example, in one situation, a first drill pipe is connected at opposed ends to the rotary earth bit and rotary head, respectively. The borehole is formed to a first depth in response to rotating the first drill pipe and earth bit with the rotary head, and forcing them downwardly through the formation. The rotary head is lowered along the tower as the first drill pipe and earth bit move downwardly through the formation.
The rotary head is disconnected from the first drill pipe and raised upwardly so a second drill pipe can be connected thereto at one end, and threaded to the first drill pipe at an opposed end to form a pipe interface. The borehole is formed to a second depth in response to rotating the first and second drill pipes and the earth bit with the rotary head, and forcing them downwardly through the formation. The rotary head is lowered along the tower as the first and second drill pipes and the earth bit move through the formation. It should be noted that the second depth is greater than the first depth. The borehole is formed to a desired depth by repeating these steps with more drill pipes.
The drill string is removed from the borehole by raising the drill string with the rotary head and disconnecting the drill pipes from each other. For example, in one situation, the first and second drill pipes and the earth bit are raised by the rotary head so that the second drill pipe extends through the tower. The first and second drill pipes are disconnected from each other by “breaking” the pipe interface and removing the second drill pipe from the tower. The rotary head is lowered through the tower and connected to the first drill pipe. The rotary head is raised through the tower and the first drill pipe moves upwardly in response. The drill string is removed from the borehole by repeating these steps for a desired number of drill pipes.
There are many different systems used to disconnect the drill pipes of the drill string from each other. For example, the drill pipes can be disconnected from each other using impact and non-impact break-out systems which “break” a pipe interface between the drill pipes. Examples of break-out systems are disclosed in U.S. Pat. Nos. 5,791,206 and 6,817,271. However, these systems fail to consistently break the pipe interface so the drill pipes can be disconnected from each other. Oftentimes, multiple attempts are needed to break the pipe interface, which wastes time and increases costs.